THE GASTROINTESTINAL SYSTEM Rita Daniela Dávila MD Adapted from Drs. Melvin Braimen, Raymond Lee, CCSF
THE GASTROINTESTINAL SYSTEM
Rita Daniela Dávila MD
Adapted from Drs. Melvin Braimen, Raymond Lee, CCSF
The Gastrointestinal System
Group of organs involved in the process of digestion
Extends from the lips of the mouth to the anal canal
Accessory structures and glands
Gastrointestinal system
Mouth and Salivary Glands
Salivary secretion
Alpha-amylase begins starch digestion
Neutralizes oral bacteria acids
Mucins lubricate food
Diseases of the mouth and salivary glands
Cavities Aphtous ulcers (canker sores) Herpes simplex Oral Candidiasis (thrush) Oral Cancer Mumps Sjogren’s syndrome Salivary gland tumors
Herpes simplex
Oral candidiasis
PHARYNX
Muscular tube involved in deglutition
Diseases of the pharynx
Viral pharyngitis
Streptococcal pharyngitis
Epiglotitis (croup)
Peritonsillar abcess
Streptococcal pharyngitis
ESOPHAGUS Muscular tube (10”) that passes food from pharynx into stomach
FUNCTIONS:
Connects pharynx to stomach
Peristalsis(contraction of muscles)
Signs and symptoms of esophageal disease
Heartburn- Due to gastroesophageal reflux
disease
Dysphagia- Difficulty swallowing
Diseases of the esophagus
Gastroesophageal Reflux Disease (GERD)
Achalasia
Esophageal Cancer (5th most common cause of cancer in adult males)
GERD
Achalasia
Abdomen
STOMACH Located between the esophagus and small intestine
FUNCTIONS:
Secretes enzymes and acids to aid in food digestion
Muscular contractions
STOMACH SECRETIONS
Mucus Lubricant, protects surface from acid
Mucous Cells
Intrinsic factor
Vit. B12 absorption Parietal Cells
HCl (Hydrocloric acid)
Kills bacteria, breaks down food, activates pepsinogen
Parietal Cells
Pepsinogen Precursor of pepsin Chief Cells
Gastrin Stimulates acid secretion
G Cells
Signs and symptoms of stomach disease
Hematemesis (vomiting blood)
- Commonly due to Peptic ulcer disease
Melena (dark stools)
- Bleeding proximal to duodenojejunal junction.
Diseases of the stomach
Hiatal Hernia
Gastritis
Peptic Ulcer Disease
Stomach Cancer
Hiatal hernia
Peptic ulcer disease
Small Intestine
Small Intestine: 30 feet
Absorption of most of the nutrients
Large intestine
Large Intestine: 5 feet Absorbs water from wastes creating stools Stool enters the rectum where nerves create the urge to defecate.
Defecation
- Rectum fills with fecal material, contracts and internal anal sphincter relaxes.
- Rectum filled with 25% of capacity, there is urge to defecate.
- When is convenient to defecate, external anal sphincter is relaxed voluntarily.
- Smooth muscle contracts, forcing the feces out of the body.
Signs and symptoms of bowel disease
SMALL BOWEL Colicky pain:
- Pain followed by a pain -free interval
- Symptom of bowel obstruction Diarrhea:
- Infection,malabsorption- If bloody: infarction, volvulus, dysentery Anemia:
- Malabsorption of iron, folate, vit. B12
LARGE BOWEL Pain:
- Appendicitis, inflammatory bowel disease (IBD), diverticulitis, peritonitis. Diarrhea:
- Infection, laxative abuse. Tenesmus Hematochezia
Small and large bowel disorders
Inflammatory bowel disease Intestinal Obstruction Appendicitis Diverticulosis/Diverticulitis Irritable Bowel Syndrome Colon Cancer Parasites
Bowel disorders
Diseases of the rectum and anus
Hemorrhoids
Anal Fissures
Perianal abcesses
Liver
Largest glandular tissue and internal organ of the body. Receives substances via portal vein: metabolites, nutrients, and toxins. Degrades toxins. Exocrine and endocrine functions
Gallblader
Pear-shaped sac (50mL) Attached to the visceral surface of the liver Stores the diluted bile, concentrates it and discharges the concentrated bile
Pancreas Wedge shaped organ.
Exocrine and endocrine gland
Exocrine, synthesizes and secretes digestive enzyme precursors
Endocrine component, dispersed throughout the organ as islets of Langerhans synthesizes insulin and glucagon.
Pancreatic secretion
Alpha Amylase Starch digestion
Lipase Fat digestion
Proteases Protein Digestion
Liver disorders
Viral Hepatitis Liver abscess Alcoholic hepatitis Cirrhosis Liver tumors
Hepatitis A
Oral Transmission
Many patients are asymptomatic. Disease is very acute. Never chronic.
Hepatitis B
Infected blood and body fluids (sexual transmission).
Completely preventable with vaccination
1. Acute disease. Total recovery, and protected from HBV for life.2. Patient unable to develop antibodies.
Chronic hepatitis that can lead to cirrhosis & Liver cancer.
Hepatitis C
Affects 2% of the population.
25% develop acute hepatitis, 85% develop chronic hepatitis.
After 20 years 20% will have cirrhosis
After 25 years, liver failure and liver cancer
Alcoholic liver disease Alcoholic fatty liver
Liver fibrosis
Alcoholic cirrhosis
Liver Cancer
Malignant cells from cancers elsewhere in the body can lodge in the liver and start a secondary growth (metastatic cancers). Primary cancers can arise from the
malignant transformation of normal liver cells or from chronic hepatitis.
The first sign of liver cancer may be jaundice, since the tumor often obstructs the flow of bile. Liver tumors are evident on ultrasound examination.
Gallblader disorders
Cholelithiasis
Cholecystitis
Gallblader adenocarcinoma
Pancreatic disorders
Pancreatitis
Pancreatic cancer
Diabetes:- Type 1: insulin
dependent- Type 2: non-insulin
dependent
Diagnostic Procedures Endoscopy
- Colonoscopy and polyp removal- Endoscopy for peptic ulcers X-Ray contrast studies Intestinal Biopsy Liver biopsy Ultrasound Stool examination Lab tests (Bilirrubin, coagulation factors, enzimes, glucose, protein electrophoresis, immune markers)
Signs and Symptoms Abdominal distention Abdominal pain Acholic stools Ascites Bilious vomitus Bloating Bloody stool Bowel sounds Constipation Cramps Eructation
Fecal impactation Feces Fever Gastrointestinal bleeding Ileus Incontinence Jaundice Malabsorption Nausea Nutrition Tenesmus Vomiting
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